Calculating instrument



y ,195o R. F. DEQMEL M. 2 51 187 CALCULATING INSTRUMENT Filed Feb. 24,1945 8 Sheets-Sheet l INVENTORS R/c/m/m FDBMEL W/u/AMA. 8146/1 BY/WMATTO R N EY July 25, 1950 R. F. DEIMEL EIAL CALCULATING INSTRUMENT 8Sheets-Sheet 2 Filed Feb. 24, 1945 I i: ILK? ATTORb lEY July 25, 1950 R.F. DEIMEL EI'AL CALCULATING INSTRUMENT 8 Sheets-Sheet 3 Filed Feb. 24,1945 INVENTORS P/C 194/?0 F: Df/MEL W/ZZ/flM 4. 5L 6 6/1 BY v ATTORNEYJuly 25, 1950 R. F. DEIMEL arm. 2,515,137

CALCULATING INSTRUMENT Filed Feb. 24, 1945 8 Sheets-Sheet 4 raw/3: G

July 25, 1950 R. F. DEIMEL ETAL CALCULATING INSTRUMENT 8 Sheets-Sheet 5Filed Feb. 24, 1945 INVENTORS PIC/ 4RD E DE/MEL W/LL/KIM /9. BL QCKATTORNEY July 25, 1950 R. F. DEIMEL ETAL CALCULATING INSTRUMENT 8Sheets-Sheet 6 Filed Feb. 24, 1945 INVENTORS ATTORN EY July 25, 1950 R.F. DEIMEL ETAL CALCULATING INSTRUMENT 8 Sheets-Sheet 7 Ink/ 78////7j-E/1 Filed Feb. 24, 1945 INVENTORS RICH/4RD F DE/MEL ILL 6 /34 H.BL/QC/f 5W ATTORNEY July 25, 1950 R. F. DEIMEL ETAL 2,515,187CALCULATING INSTRUMENT 0 a 2 Min.

' o 1 2 Min- INVENTORS RICH/2R0 EDf/MEL ig/t/AM I4-ELI9CK ATTORNEYvariable quantity,

Patented July 25, 1950 Richard Francis Deimel, Hoboken, and WilliamAlexander Black, Montelair, N. J., assignors to General Time DelawareCorporation, a corporation of Application February 24, 1945, Serial No.579,582

23 Claims.

vices for automatically and directly rendering an arithmetical averageof the changing value of a or of observations, readings, or indicationsof an observation instrument during a continuous sight, and the objectof the invention is to provide an improved mechanical calculating deviceof this kind.

It is customary, when making observations or measurements that aredependent on the human faculties, to take a number of readings andutilize their average value, in order more nearly to approach accuracy.This is especially desirable when the observations are made underdifficult or trying conditions as, for example, in making celestialobservations from aircraft. Accordingly, the purpose of the invention isto provide a calculating mechanism which will give directly, and withoutthe time and labor of mental calculation, the average value measuredwhen taking a-continuous sight with such an instrument, for example, asextant, octant, transit, range finder, or other angle or distancemeasuring instrument.

The basis for the determination of the location of aircraft or marinevessels in degrees longitude and latitude at any given time is ameasurement of the altitude at that time of a celestial body such as thesun, moon, or certain stars. The altitude of the celestial body is itsangle of elevation, that is to say, the measurement to be made is theangle between a line passing through the celestial body andthe pointwhere the measurement is made, and a horizontal plane passing throughthe same point.

,In order to know accurately the location of the point of observation itis necesary to measure this angle with a high degree of precision. Thereare many factors which affect the accuracy of altitude measurement,particularly on aircraft. One such factor is the influence of minorerratic accelerations, which the aircraft may be undergoing ,during thetime the readings are taken, on the bubble which is commonly used insuch observation instruments as a means of determining the horizontalplane. Observations are not made when the accelerations are large. Othersuch factors are the difficulty in taking or maintaining a sight on thecelestial body caused by the motion .of the aircraft, and the fact thatthe measurement is dependent on the human faculties.

It is customary when making such observations, either to take a numberof readings and obtain their average value, or to take a continuoussight on the celestial body during a more or 2 less prolonged period oftime; about two minutes is usually sufficient. In the latter case it hasheretofore been necessary, either to estimate the reading of theobservation instrument at the middle of the period of the observation,or to utilize mechanism for integrating the average reading during thetime of sight, which required the calculation of a correction factorfrom the readings of a number of different dials, and the application ofthis factor to the final reading. The purpose of the present inventionis to provide a calculating mechanism which will give directly,'andwithout the time, labor, and effort of mental calculation, the averagevalue of observations with a sextant or other observation instrument.

Since the position of a celestial body with respect to a point on orabove the surface of the earth changes continuously with the time, inmeasuring the altitude of the body it is desirable to ascertain itsaverage altitude during the period of observation. Accordingly, theinvention also aims to provide an improved device which, when used on asextant or other appropriate altitude I measuring instrument will, atthe end of the period of observation, automatically and substantiallyinstantaneously render the average altitude of the celestial body duringthe period of observation and without mental calculation or estimatingof any kind.

In making observations from aircraft, due to its own rapidly changingposition and the presence of clouds, or otherwise, it is oftenimpossible to take readings during a predetermined period of time, evena period as short as two minutes. Therefore, a further purpose of theinvention is to provide an averaging mechanism for sextants and the likeby means of which a dependable average measurement of the altitude of acelestial body can be obtained independently of the length or durationof the period ofv observation, and which will so nearly correspond withthe true altitude that'the position of the observer can be known moreprecisely than heretofore.

It is important in the operation of aircraft that the navigating officerbe relieved of even simple that he may devote mental calculations inorder his attention to otherduties. Another object of the invention is,therefore, to provide an averaging mechanism for sextants and the likewhich, in addition to averaging automatically the altitude of thecelestial body during a previously undetermined period of observation,also indicates 'one-halfthe period of observation.

The construction and operation of the calcuhas a variety of applicationsand is capable of averaging the, values of. numerous; other variablequantities -..such,a for --=example, as temperature,

pressure, Velocity, power consumption or power L production, the flow offluids, etc.

In the accompanying drawings:

Fig. 1 is a view indicating theprincipal elements of a sextant, being asectipngtakenonythe line l-l of Fig. 4;

Fig. 2 is a perspective view of'uthesextant looking at the instrumentfrom its opposite side, with the cover of its casing removedtcshowtheegean ing interconnecting its various movable parts;

Fig. 3 is a perspective view of the SGXtELIIU'lOIOka.

ing from the same sidejof Fig. 1, and showing the qperati etta e t t emp ovedavera i e e ism w th t ov nre o Fig, f1; a, sectional view .1 of.the mechani m. of ,the invention taken ,on the planeindicatedb the lineil it-in;.I?igs-. 3and 5, looking in thedirection o t e. nq

,Fig. 5. a .plan view of:the-averaging mechanis m with. the coverqandoutcry-drama. plate n taken on .the linet- .5 of Fig. 6

Fig. 6, is a sectionalgview takenatright angles .t .Fig. 4 and along thebroken-line6+6 of Fig. 5, ooking. .toward .the. left tasogindicated by.the r .o

, iEig; "1-. is a sectionalyiew. somewhat similarsto Fig'. 6 but takenalong the broken line 1.1 of Fig. t nd-a sc o kina wa d he fi;

ig. 8,.is. a .sectional view-taken. on,.the. line ..8- qiFigefi Fig. 9.is a .plan .view .of; the, .operating .face. of,-,the..averaging..mechanism shown in Fig. 3., with efiel'ts oi thecover and- ;upper frame plate broken Fig-., 10; is afragmentary sectiontaken on. the 1 1 .0 QIE e-B;

. Eig 11. is. aldetail .viewdoi parts 0f;-.the shutter automatic time,stop v,setting and trip mechm; .bei ng, a ,section ..taken. on .line .Il-. -i.l I- of Fig. 12 is a detail section takenon line ,l-2-.ll2 fEi 6;

g. 13 is a detailsectionotthe winding. mechanisrnt akenon linel3-.-.I3.of Figs. 5 .and l5;

Fig; a,detail,section .taken. on line 114- l 4 ig 'l E1g1ll15, isadetail section of, the winding .mechm taken unbroken line "I 5-'ll 5,of 'Fig'. 5;

' $116 is a sectional view. taken on ;.line-1;l6 jI6 5; g. 17 isanenlarged sectional ,view taken on 3. 1 111 ljQ Eie- Fig. 19-isa'sectional view taken on'line'ls lfl of Fig. 18 and'drawn tofthe samescale;

-insi de elevation of the parts of the '-averaging gmechanism; and

Fig 20w is a graph explaining the calculation --performed by "theaveraging mechanism.

Figsfi *2 l-to- =24 inclusive are explanatory diaegrammatic viewsshowing the-same parts inplan --and-findifferenttpositions.

Referring-nowto 'the accompanying :drawings,

there is illustratedgenerally-"-in-'Figs. 1; 2 and 3 mQte l-an w hw ernw r s s o a bubble sextant of the type in common use on aircraft, andalso on shipboard. Figs. 2 and 3 show the application of the improvedaveraging device of the present invention to the instrument. The sextantcomprises a housing I, on and within which are the various operatingparts, including an eye-piece 2, a reflector 3 in which may be.seen animage of. the ;:bubble in the bubble chamber 4, afixed prismatic mirror5 and a movable prismatic mirror or field prism 6. Field prism 6 ismounted on a sector assembly 1 which is ad- .justableabout an axis atright angles to the plane 'of'Fig. 1 by means of a rotatable controlknob 8 -..-.-.which:1is operatively connected with the sector assemblyizbymeans of a gear train indicated generally by-nu-meral 9 and.illustrated in Fig. 2.

Knob 8 is'manually rotated during the operation ..oithesextanttoefiectcoincidence of the image of the bubble and the image of the celestialbody. fililithathis adjustment made, an odometer type of counter inactuated by the gear train 9 indicates the, altitude angle in degreesand minutes.

qThearotation. of the sextant control knob 38 .3150 :causes. through,-g,ear:- train; 9;- the. rotation :of a shaft I I which operates; theaveraging: mec a- .nism. For this purpose 'shait 1 I terminates,.& at-..theopposite; end from, that shown in. Fig: 2 in a head: 12: (Figs. 1:and 4) having a driving-pin l3 by;means of which operating connectionwiththe averaging mechanism ismade. Iihe. driving head I2. is :located-,at.-.the center of the, bottom :of a

circular recess A l in the sextant housing I.

- The .averaging:.mechanism isflocatedtwithin a stepped.- cylindricalhousing i5, .the inner; .-.and -smaller.end of- Which-is receivedzwithincircular recess/1M, as showninFig. 4. Therouter; end-of thousingrl 5 isclosed by a circulanirame platealii and acover H. a Shaft l tand-sector. assembly I which mounts-the field prism are-gearedzby-geartrain 9 .to2.turn through the same angular.distances for any givenangular movementmf knob 1 8. lso; .eas is customary,.; thearrangement;of gear train 9-is such: that for each.-c,omplete:revo- 'lution ;of;.knob 8 these parts :and the counter. I ll moverten degrees ofanglerofelevation-or altitude n l The. {averaging mechanism comprises :an'iindl--cating men' berinv the formof a flat; circular'rdisk -l 8,"an-averaging-member :inrf the formofi a rotatableHcylindricalwdrumylllygand a;- transmission ,mechanism orrgea'ring arranged totransmit-moetionbetweeni disk 1.8 and drum l9; which is2-.in- -dicatedgenerally .by' numeralifi. ShLaftz I: I amight -more accurately: bereferredtto as -thecindicating 'member of.- the averaging .Emechanism i:since: it

moves or is angularly adjustediaccordinggto the value .of; .thezaltitude'zangle asidetermined byl'the sextant mechanism;s'anduitsrangular; positionais :shown by-icounter'il l3.

1 Disk l8'rotates' with shaft H-=and is c'entered on it by :means' of apin 2l which= p1 oject$-from 1 thecenterof head' 2 and 'is --receivedwithin a central aperture in the disk. Briv-ing pin --l 3-is receivedwithin a closely fitting:radial -slotffl2-in the bottom of the disk.This-- provides a-releas- :;able connection permittingthe-averagingmechanism -to beremov'ed from the -sextantfor-repair or ---replacement.To prevent distortion of the disk and to enable it to turn with aslittldric- 7o tion aspossible. itis supportednear its periphery byaseries o'f balls -23-held-= in a cage 24'- rolling on a circulartraclc'25.

The axisof drum- IB-isparal1elto the-face of disk l 8 and intersects theprojection 'ofthe axis of the disk;-=as will be u-nderstood from Figs?-4;

' and 7, and also from 35 are provided to reduce friction.

the diagrammatic views to 23 inclusive. Drum I9 has integral shaftproiections 26' at each end by means of which the drum is supported forrotation (preferably in ball bearings as shown) by means of a yokemember 21 (Fig. '7) which is pivoted at 28 to brackets secured to aframe structure '29 mounted within housing I5. The axis of pivots 28 isparallel to the axis of drum I9 and to the surface of disk I8.

The friction gearing or transmission mochanism 28 comprises two balls 30and'3I and a cage 32 which is mounted on a carriage 33 movable parallelwith the surface of disk I8 (Fig. 8). For this purpose carriage 33 movesbetween two par allel guides 34 I equidistant from the center of diskI8. Rollers The two balls 30 and 3! are held by cage 32 always incontact with each other and with ball 30 contact with disk I8 and ball3I with The arrangement is such that the travel of carriage 33 carriesthe two balls from the center of the disk outwardly in a radialdirection, and durextending across the housing I5 always in. drum I9.

ing this movement ball 30 is maintained in contact with the disk onthrough its center and ball 3| makes contact with the drum along alongitudinal element of the drum. This longitudinal element, the axis ofa straight line passing" the drum, and the straight line through the center of the disk, are substantially coplanar. line through the points ofcontact between ball and the disk, between the ball 3I and the drum, andbetween the two balls, is perpendicular to the plane of the disk andpasses through and is per pendicular to the drum axis. This line will bereferred to as the contact line.

The pivotal mounting of drum permits the two balls 30 and 3I to beplaced under pressure along the contact line with enough force toprevent slipping at the points of contact with each other and with thedisk and drum. This pressure is produced by means of a flat spring 36(Fig. 7) which is fixed to frame plate I6 I9 on yoke 2'! and whichengages the outerend of a pin v3I whose inner end bears upon yoke 21.

When the value of a varying quantity is to be averaged with respect totime, a clockwork mechanism is provided to move carriage 33 at aconstant rate outward from the position shown in Fig. 8 where thecontact line passes through the center of disk I8 to any position atwhich it is desired to terminate the averaging period. The main springof this clockwork mechanism comprises two coil springs 38 (Fig. 8), therighthand ends of which are attached to and whose left-hand ends arefixed to housing I5.

The clockwork mechanism will be described in detail later, includin thebalance wheel escapement mechanism indicated generally by numeral 39which controls the time rate or velocity at which the carriage 33 movesoutward. There is a time dial 4i], and a rotatable time index 4| havingan index mark or hand is geared to indicate one-half the duration of theaveraging carriage 33 I cent the edge of disk I-8, the clockwork mechanism is stopped automatically, and simultaneously a shutter 43 (Fig. 6)is actuated to cut off the admission of light to the eye-piece 2,thereby notifying the user of the instrument that the end of theobservation period has been reached.

The duration of this maximum observation period may conveniently be twominutes, in which case time dial 43 may be graduated to seconds and makeone complete revolution in sixty seconds. However, the mechanism may beconstructed to have this period longer or shorter than two minutes ifdesired. If the observation period is less than the maximum the releaseof button 42 v stops the clockwork.

The turning movement of drum I9 is shown by means of a drum index dial44, the construction of which will be described in detail later on, butwhich in general is rotated by means of a gear 45 fixed to the end ofone of the shaft projections 26 of drum l9. Gear 45 meshes with a secondgear 46 which causes the rotation. of index dial 44. Alongside of indexdial 44 is a direction dial ll. These two dials are arranged to bevisible through a Lucite window 48 mounted on cover Il.

Index dials 4 3 and 47 carry index marks 44a and 41a respectively, whichat the start of each later, are brought into registr with a stationaryindex mark 49 provided on the inside surface of a Lucite structure 50which covers dials 44 and 41 where they project through frame plate I6.The purpose of direction dial 4! is to show whether drum index 44 hasmoved clockwise or counter-clockwise from the fixed index mark 49 duringthe averaging period.

The general operation of the averaging mechanism of the invention may beunderstood more especially from Figs. 20 to 24 inclusive, although thespecific mechanism shown in Figs. 1 to 19 inclusive contains featuresyet to be described and whose operation will be detailed later on. Inthese figures the parts of the averaging mechanism are illustrateddiagrammatically for the sake of clarity. The operating shaft II for theaveraging mechanism is considered as having the disk 5:3 of theaveraging mechanism fixed directly to it instead of being releasablyconnected therewith as shown in Fig. l and previously described.

Also, the index dial 44 takes the form of a pointer or hand, rotatingwith respect to fixed index mark 49 and driven by a bevel gearing 5|from shaft projection 26 of drum I9, in order to show the extent oramount of rotation of the drum. However, one important feature of thisinvention is that the numerical value of this amount need not be known;the drum radius may have an convenient value. Ball drive 20 moves to theright from the center of disk I8 instead of to the left as shown in Fig.4. A stationary scale 52 graduated in degrees cooperates with an indexmark 53 on disk I8 to indicate the angular position of the disk, and theoperating knob 8 of the sextant is shown as connecting with operat ingshaft II through a bevel gearing 54 which corresponds to gear train 9 ofthe sextant.v

Assuming that the ball transmission 20 in a two-minute period moves fromthe full line position shown in Fig. 20 to the dotted line position, andthat the altitude of the celestial body increases during this periodfrom seventy to eighty degrees (this change being exaggerated for thesake of clearer illustration), index mark 53 will be opposite seventydegrees on scale 52, the posiq I move' the ball drive angular positionof .poirit A.

' transmission mechanism disk and shaft 26 of .ratio depends on the ofball drive it from the center of disk; I:8,"and

rotates disk i8 through ball drive 'ilto drum i9, thereby causindex mark"5.9.

" "been tion to which-diskl8.will be turned by knob 8 at thecommencementof theobservation"(fFig'.21).

At this instant starting' button '52 ispressed and I the clockworksmechanism commences to .28 toward the'iright. 'The observer keeps acontinuous sight on the'cel'estial body and, in so. doing, turns knob 8to holdthe imag v of the body in' coineidence'with the bubble.

The index mark 53 on disk is is thereby advanced -:away from theseventy-degree mark and toward the eighty-degree mark; In" thegraphatithe lower part of Fig; 21 the initial seventy-degree diskilB isindicated byi'the The ball drive 28 constitutes, with disk I8, acontinuously variable ratio friction" gearing or between'shaft' I I ofthe drum it." The transmission distance or the contact line increases asthis distance increases. The-bs'erver, inturning knob 8 to maintain thecelestial body in coincidence with the-bubble, gradually and thisrotation is transmitted ing index M to 20 will have reached the positionshown in Fig.

22, disk l8 having been turned .until index mark 53 isoppositeeightydegrees on sca1e52, this .value being indicated at the point B inthe graph. .If readings had been plotted at intermediate positionsbetween the beginning and end of theobservation period a curve wouldhave been drawn somewhat as 'ations being caused by one Or more of thefactors mentioned previously.

shown at AB, the-fluctu- The angular position of drum I9. at the end of'the observationperiod is shown by indeir'M in Fig. 22. .'The amount ofthis angular displacement of drum I9, caused by the angular move- "mentof disk 18 during the observation period while'the ratio or thecontinuously variable ratio gearing is being increased at a constantrate commencing at zero, is such that if this angular displacement istransmitted to disk'IB at the final ..ratio of the gearing, that is tosay, while ball "drive2ll is held at the position shown in Fig. 22,the'angular position of disk I3 will be modified or shifted to aposition which represents the avervalue of the variable quantity duringthe averaging period, in this case the altitude ofthe I celestial bodybeing observed.

Fig. 23 illustrates this. Operating knob'8 has rotated in a direction tocause index to be returned to coincidence with stationary index mark 49.That is to say, index 4Q has been returned to its original position bymoving it in a direction opposite to that inwhich it moved duringtheobservation period. In so doing, diskl'B has been moved backwards untilindex mark53 is opposite a value of seventy-five degrees on scale 52,which corresponds to the" position C shown in the graph at the lowerpart of Fig; 23, and which is the average angular position of disk I8during the averaging period. In the above description'of the operationofthe averaging mechanism'as used in connection with a sextant; only atwo-minute 'fixed period .of observation has been considered. It will be"understood howeveri that the period of observato say; '"view before"the balltransmissionZli has reached tion needinot befixedorpredeterminedi That is if a cloudcuts' .offthe celestialbodyrr'omthe'lirnit of its outward radial movement which, in

:the' mechanism illustrated, requires two minutes,

"or if for'any'other'reason it isnecessaryi'ondeterminate the'period ofobservation before thetwo minutes have" expired, the-observermayrelease'the'buttonf i2 and thereby stop the .further "advance ofballtransmission 20.

" "might be released at" the end of 80 seconds, in

which event the bal-ldrive would have reached *therapproximate positionshown in this figure. "During-this time disk 18 mighthave-beenrotated byknob 8 "to the *seventy-seven-degree position indicated by thepoint Ein" the graph atthe bottom of Fig. 24-; and this-'would-have caused theindex dial "M 'to be turned to*thefull-line j position of Fig'fi2i. Uponturning knob 8, with theball drive-20 remaining'in the =final positionwhich is shown inthisfigure, until" index dial- 44 hasbeemreturned toits initial-"position in registrywith stationaryindexmark tSJ, disk t8will Y --ha-ve been moved back to the average value of thealtitude angleduring the ts second period, ---which can be read directly-from thescale 52 as line position oi -index "seventy-three and one-h'alfdeg-rees: The dotted mark-53 indicates this position; and in the graphitis indioated-by the point F.

In both of the illustrations of operation above given, the celestialbody has been assumed-to be -rising rather than declining, so that theaverage value of its altitude is less than the altitude at sthe end of 7the period or observation. Hence in order-t0 obtain the value of the:average angle,

disk I 8 was turned backward." :In the event, however-,cthat a sight istaken whilethe celestial body is1-declining: instead of rising, theaverage: value :of the'altitude will be: greater thantheialtitude .attheend ofithe observation. Accordingly, disk iIBWill.bezadvancedzuntil.index dial-M is inregistry withstationary..index'.mark 49,-. instead of being turned backward... In-thecase of a: sight .iztaken' lwhile .the: celestial body: is risinggzindexdial 44.will-b'eiturned:clockwiseuntil it is brought into:registryiwithrstationary. index mark. 49, while iIIWhGJ-CaSGOf a"sighttaken' while the celestial body; is-.declining..th'e indexdial willbe turned s'counter-zclockwise. a; .:In' bringingindex dial A4 back tothe stationary nindex: markiw it is always moved in the direc-.-.t1on;opposite to -.its.movement.rluring theobservationperiod.Consequently, tozenablean observation'tob'e taken as quickly aspossiblethe averraging mechanism is provided'with thedirection dial 4'!(Fig.5) .previously referred.to..' The ar- .xrowsuon. thistdial show.the .direction inwhich indexdial M-should bemoved-at the end of theobservation period.

Direction dial 4'! is rotated in the same-direction as index' dial M bymeans of the gearing shown in Figs'. 5 and 6; This includes a largegearmeshing withgea-r land fixedtoa-hubtt on the outer end of which is agear 51 which'meshes with another-gear 5Bwhich drives directiondial 41.Hub 56' rotates on a fixed-pin which constitutesone of-the pivots lB forthe yoke 21.

It will be understood that in taking' an actual observation with asextantjequipped with the device ofthisinvention,asishown iniFigs, 1to"19 inclusive."the-altitude angle will be readon' .the

counter which, in the actual mechanism, takes the place of thediagrammatic index 52. Furthermore, one-half the time of the averaginperiod can also be read from the position of the time index 4| withrespect to time dial 40. In the case of the first two examples ofoperation above, time index 41 will make one complete revolution whichrequires 60 seconds, whereas in the third example, where the duration ofobservation was 80 seconds, time index 41 will indicate 40 seconds. Thetheory of the averaging mechanism of the invention may be explained incon" junction with Fig. 20. In the graph shown in Fig. a 11 is the anglethrough which. the disk 18 has been turned during the time it has takenthe carriage 33 to move outward to a position a: from the center; yAv isthe average angle and the time of observation is t. Then tz =Area underthe (y y curve ty =Area of dotted rectangle 1! J; a X dy=Area above (y ycurve whence An increment of angle dy of the disk 18, with carriage 33at X turns the cylinder of radius 1", through an angle Xdy f and thetotal drum l9 angle is E2 back to its initial position f 2% 111 7' turnsthe disk back an amount t J;/1 g and thus according to Equation No. 1subtracts this term from (112 average value of my.

Referring now to the details of construction ofv the sextant averagingmechanism shown in Figs 1 to 19 inclusive, the gear traininterconnecting the carriage 33 for the ball transmission 2!) beginswith a rack 59 (Fig. 8) with which meshes a gear 60 which is fixed tothe lower end of a stub shaft 6| (Fig. 6). Gear 60 in turn meshes with agear 62 which is fixed at the lower end of a second shaft 63 whichcarries the time index dial 4| at its upper end. Shaft 63 preferably ismounted to rotate in ball bearings, (as shown in Fig. 7) and just abovethese bearings there is a large gear 64 which drives the escapementmechanism 39 through a train of gears to be described presently.

Gear 64 is not fixed directly to shaft 63 but is connected to it by aball clutch 65 shown in Figs. 7 and 14. Shaft 63 turns in a directionopposite Turning the cylinder through an angle and sets the counter tothe 10 to that of the arrow shown in Fig. 14 under the action of mainspring 38 while the clock mechanism is running to drive the escapementmechanism through ball clutch 65 and gear 64. Ball clutch 65 permitsshaft 63 to be turned in the opposite direction in winding the clockmechanism. For this purpose a gear 66 is fixed to shaft 63 just abovegear 64 and with gear 66 there meshes a larger gear 61 which rotatesfreely on an enlargement 61a near the upper end of a shaft 68 which isparallel with shaft 63 (Figs. 6 and 13). A winding knob 69 (Figs. 13 and15) is pinned to the outer end of a short shaft 10 arranged to turn in abearing aperture in a thick plate 1| mounted on the outside of frameplate 16. aligned with shaft 68 and, by mechanism to be described whichis mounted on the lower end of shaft 10, the turning of knob 69 effectsthe turning of shaft 68. This turns gears 61, 66, 62 and to rotateshafts 63 and 61 and shift carriage 33 to the right as shown in Fig. 8to wind main springs 38 and simultaneously to position the contactlineof the ball transmission 20 on the center of disk I 8. During suchoperation shaft 63 rotates in the direction of the arrow shown in Fig.14, and because of the presence of ball clutch does not impart rotationto driving gear 64 of the escapement mechanism 39.

When the winding knob 69 is released, main springs 38 immediately tendto rotate all of the shafts and gearing referred to in the oppositedirection, and, when button 42 is pressed, shaft 63, rotating in thedirection opposite to that indicated by the arrow in Fig. 14, turns gear64 through the ball clutch mechanism. Gear 64 drives the escapementmechanism 39 through a train of gearing shown in Figs. 9 and 5. In thistrain gear 64 drives a gear 12 which is made compositely with anadjacent larger gear 13. Gear 13 in turn meshes with a large idler gear14 which drives pinion 15 of the escapement mechanism. Idler gear 14rotates on a stub shaft structure 16 (Fig. 4) which is mounted on frameplate I6. The composite gears 12 and 13 have a similar mounting (notshown). Escapement mechanism 39 may be of any suitable constructionhaving a balance wheel 11 (Figs. 9 and 10).

The mechanism for starting and stopping the clockwork mechanism is alsoshown in Figs. 5, 9 and 10. A flexible resilient arm 18 made of aslender spring wire and having its end bent to engage the outer surfaceof balance wheel 11 is attached to a hub 19 which is fixed to a rockshaft mounted balance wheel 11. A comparatively stiff coil spring 8| hasits movable end joined to an arm 82 which is also fixed to shaft 80 andtends to rock shaft 80 in a direction to 18 to frictionally engage .theouter surface of balancewheel 11 and h tionary. An actuating arm 83,also fixed to shaft is engaged by the inner end of a rod 84 on the outerend of which trip button 42 is mounted. Rod 84 slides in an elongatedbushing 85 which is fixed to the housing [5 and a pin 86 engages theinner end of bushing 85 and serves as a stop for limiting th m spring 8l.

Button 42 is both button. When it is pushed inwardly the rocking ofshaft 80 causes flexible resilient arm 18 to swing in the direction ofthe arrow shown in Fig. 9. The location of rock shaft 80 with respect tothe pivots of balance wheel 11 being such that ovement of the parts bycoil Shaft 10 is parallel with the axis of the cause flexible arm oldthe balance wheel staa starting and a. stopping duringthe firstpartofthismovement there isj sufficient frictional engagement with the surfaceof the. balance wheel to start. the balance wheel: j in'r'otation.'Thereaftentheiend of .arm18'moves out of contact with the; surface "of.thetbalance r wheeliand permitsthe balance wheel. to oscillate. as longas it is desired 'to'operate the clockwork; mechanism. When button .92is released, the end" ofarm 18 returns into. .frictionalengagement withbalance wheel. 11 and 'stopsthe'mechanism.

At the 1 start .fOf each "observation with the" sextant'it is notonlyfnecessaryto windtheclock 1 work-mechanism and setthe. contactlineof bial'l"i transmission 20 orrthe' center of disk ..I.8,ibutals0tobringthe index marks Ma/andliz of thein-idex'and'direction-dials*M'and 41 respectively; into registry withthestationary index mark' 491*; This is done by means of the mechanismshown" more particularly'in Figs. 1'7,'18 and 19.

The two indexdials-M and 41 consist or 'two similar" cylindrical'members, each 'shapedsome thing likeatinyshallow' pan. 1 They arearranged with their open-sides facingeach' other as shownin Fig? 17,leaving a hollow space between-them." They are "mounted on a sleeveshaft '81, index dialM having a hub 8 B and. dial 41 having a similar'hub BILfthe -inner' ends of which abut"-" against theopp'osite"sides-of a heart-shaped-oam 90 which is fixed to sleve sha ft 81-by'means of and 89 arefi held- -respectivelyby'::means of *snap rings BZ'andJ -93 which are receiv'ed in circulan 1 grooves on the surface ofsle've shaft 81. The"-'- arrangement of th'ese' parts is such thatindexdials and il' may'tui'n easily on shaft 81. 35 lndex aidia l 44 i has ia roller 94 coactingwith hearti shaped "cams flfij this rollerbeingacarried A at --therouter I end. er an arm" .95 which is pivoted-'at 'iitS'lOppOSite- Tend-. to'aa post: 95 which =projec'ts' fromrtheiinside' wallaof dial -4;'-'I.-1 ',A spring .2911Sur- 40rounds=.post=06 andis arranged to maintain "roller. 1-1: 94 inengagement: with-cams!!!) Directiomxiialzfi 41 is providedvwithz'asimilarzrrolle'r:Ma -mountedw in precisely the; same :manner"as-rollerafl 'to renew gage: heart-shaped:cam-:90. 1 By. means?ofz'jtheserollers and them-spring mountings the .dialswM and 41 seekpositions iniwhich rollers: 9?!and-94am. are :at the toner .heartsha-ped'cam 90,. as shownin Fig. .18; in which. positions-thev'index'marks 44a and flaaare at-thetop-and in-registry with-:

the. stationaryindex mark 49.'

sleeveasha-tt .81 is so-mounted as-tohold cam 90 always in thisposition, The sleeve is mounted I.

in an aperture. in .the. right-hand end of yoke..=.

member-721, asyiewedin Fig.5. To permit shaft,

81'have limited sliding movement in this -aper ture, for a purpose.whichwilljappear' presently, andat the same. time maintain. cam 90in.fixed.... angularlpositiom'a keeper.98 arrangedrto'engagea flatsurface. 99 j at the;- inner end of shaft a1 (ei g'sqsandln'tq v Index.dials lfandllljare rotated bYLgears .46 T andi 58Tdurin'g..an,observation period as .previ-. .I' ously.described,,causing their indexmarks Ma'j and'ffla" to 'moveawayfrom thefstationarylindex .w'

mark MjfTIi'e motion of gears Afiand 58 is trans-,- mitted toindez'rdialsfml and 41 by'means of .rje-l leasablefribtion "clutch"rings I00 and I01 Lear-,1, ried respectively by gears 46 and 5 8 andadaptedw to frictionally engage the outside faces. of the;respe'ctive'dia'lsM and '41." Inflordertdreset'index'dials Mia'nd .41atfzero. positionfwithitheir indei'r marksd lwand Maiin" registrywith'stationarydndex marki49f'prior to j making an observation; clutch'ringsI 00 and" HI I '75 thefindex dials "to turn. to their-i-zero?position...v

For this purpose .the hub of gear58 .is slid to .the..--

right as viewed in Fig; 17 to release clutch ring IOI from indexdial.41, and then sleeve shaft. 81"itself, with all of the parts carried.thereby,,.,-. is slid in the same direction tomove .indeX-dial. 44 outof engagement with clutch ring--I00,',To' prevent gear v lt andc1utch'ring100 from sliding with shaft 81jthezhub of-gear ehas afiangeIIJZ LT engaged byla finger I03'ha'ving. an .arcuateend r andwhich is 'fixedto the end ofiyoke' member. 21, as shown in Fig; 17'.

Th'eshifting. movement of gear 58' and clutch ring IN "is accomplishedby means of .a" rod I04? which is received within sleeve shaft Bland hasa flanged head IOB-to engage a cap lllfi threaded onto the hub of gear58- and .alsoto .engage the end of this gear hub. Rod I04 has anactuating pin I01 nearaits dnnenend projecting upwardly through a closedslot I08 in sleeve 81 and an open-ended slot I00 in yoke member 21.Actn-:

'ating pin I01 is engaged by the side walls of a closely fitting sloti'n-an. index release lever III which is pivoted at H2 to yoke 21 andwhich, at its lower end, has a, sickle-shaped cam I I31 to be referredto later.

Normally, that-.v'is when *clutchzrings H10 and I0] are in engagementwith index dials 44 and 41; release lever-"II I -isdrawrr'towardthe-leftas shown in Fig. "5 by means of a coil'springd It,a one end of which is fixed to the-arm=and=-tl1e'-- other to anextension ofrkeeper 96. This forces actuating pin I01 and rodefll ltoward the left as viewed in Fig. 11, causing head I05 to move the hubof gear 58 towardthe left and'thereby press clutch ring IOI intoengagingposition with index dial 41. Index dial 11 is thereby urgedtoward theleft and. withit sleeve shafts] and indexfili; the face ofwhich is pressed against clutch ring I00.

When release lever I I I is moved about its pivot toward the right, asshown in Fig. 5, it moves actuating pint: 1-01.1 towardthemight;*sliding rod r I04 within sleeve 81. A coil springull5 is .Ldisposedbetween the left-hand. end of rod I04 and the bottom of the hole inisleeve shaft 81 in which rod I04 is received. Spring I15 overcomes thetendency for sleeve'shaf-t 81 to beslid toward the left by thefrictionof rod- Ifi liwithin it. The movement of roddMZauses head I05 tobear against...cap ,I 06 and force gear .58 andits. .ring IOI lout .crcontact withlth surface of index-dial' 41. "The side of pin I01 thenengages thelrighti-w hand .end. of slot .I 08 and the continuedmovementof .pm m toward the right thereby forces. sleeve.v shaft.;81.ltoward.-the.right, carrying...with it all the parts supp rtedbyitandshifting index. dial 44 I out of frictional. engagementwith. frictionring I 00. l..The-..sequence .of these operations is,- therefore,-that..direction.dia1 41 is first released by-- clutch ring .10 I .and.immediately thereafter index dial .44. is released-from. clutch-ringI00. Heart-shaped. cam .90,..acting..on rollers 94. then causesbothlthese =dials to rotate to .their zero positions.

Index releasalever III is operatedby mechanism connected. withltheflwinding knob 69. so that when this knob is turned to wind theclock-. work mechanism it simultaneously effects thesetting ofindexdials 'M jand41If' 1 Lever :1 II is opera. atedtbymeansof .a pin .II6 (Fig. 12), .which. en-. gages sickle-shaped cam I I3 "and moves'the'lever to the right. Pin I I6 projects downwardly from the lower surfaceof a pin plate III which is fixed at the inner or bottom end of windingknob shaft 10.

Winding knob 69 requires only about a half turn to fully wind mainsprings 38 of the clockwork mechanism and move the carriage 33 and balltransmission from its position at the edge of disk I8 to its startingposition at the center of disk I8. During such a one hundredeighty-degree rotation of winding knob 69 pin plate II'I moves in thedirection of the arrow shown in Fig. 16 away from a stop pin I I8 andwinds up a small spiral spring I I9, one end of which is secured to thetop side of pin plate III and the other end of which is fixed in a postI20 which projects downward from frame plate II.

In addition to pin H6, pin plate III also carries a winding pin I2I.This pin projects downwardly from the outermost portion of plate II! asshown in Fig. 16. As previously described, winding gear 6'! turnsloosely on shaft 68 which is in axial alignment with winding knob shaftI0. Winding gear 61 also is positioned in proximity to, but spaced from,pin plate II! and has a driving pin I22 projecting from its uppersurface (Figs. 11, 12 and 15). During an observation period, that is tosay, while the clockwork mechanism is in operation, winding gear 81rotates counter-clockwise as shown by the arrow in Fig. 11, carryingdriving quite, one hundred eighty adjacent winding pin I2I.

When winding knob 69 is rotated to wind the clockwork mechanism, windingpin I2! engages driving pin I22 tion shown in Figs. 11, 13 and 15,thereby winding the clockwork mechanism. When winding knob 69 isreleased by the fingers, spiral spring IIE) returns it to its normalposition, carrying the shoulder of pin plate II'I against stop IIB.Driving pin I22, however, remains in the position shown in Fig. 11 untilthe clockwork mechanism is started by pressing button 42, being helddegrees to a position in this position through th gear train and ballclutch 65 (Figs. 7 and 14).

The shutter actuating mechanism is associated with the winding mechanismjust described. It is tripped by the clockwork mechanism at the end of atwo-minute operation thereof, in other words, at the end of a two-minuteobservation when the ball transmission '20 has reached the periphery ofdisk I8. The shutter mechanism is reset automatically during the turningof winding knob 69 through the half revolution above referred to.

Shutter 43 oscillates on a fixed pin I23 (Figs. 1 and 6) which projectsfrom the right-hand side of a square tubular housing I24 which supportsbubble chamber 4. It is actuatedby' a rocking movement of shaft 68 whichhas a small crank I25 at its outer end which is connected to shutter 43by means of a link I 26. In Figs. 1 and 6 the shutter is shown in itsopen positio'nout of the path of the light entering the eye-piece tube.In its closed position the pointed tip of the shutter is interposedpartially across this light path, so as to notify the user of theinstrument that the two-minute observation period has terminated.

The rocking movement of shaft 68 to actuate shutter 43 is produced bymeans of a coil spring I2! surrounding shaft 68 (Fig. 6) which is placedunder tension by the turning of winding knob 69 during the winding ofthe-clockwork mechanism.

pin I22 nearly, but not 1 and moves it back to the posi The mechanismfor accomplishing this and for tripping the shutter to closed positionwill now be described.

Referring particularly to Fig. 13, shaft 68 has at its upper end aboveenlargement EIa, an integral head I 28. In the edge of this head thereis a setting notch I29 and a tripping notch I30, the latter having aflat cam surface IS! on one side. Setting notch I29 is adapted to beengaged by a setting pawl I32 and tripping notch I30 by a latch memberI33 which is pivoted at I34 to a part fixed to housing I5. Latch I33 isheld in engagement with notch I30 by a coil spring I35.

As shown in Fig. 11, the shutter has been set in open position by theturning of knob 69 to wind the clockwork mechanism. As soon as button 42is pressed when taking a sight on a celestial body, the clockworkmechanism commences to operate and winding pawl I32, with its holdingscrew I38, will commence to mov in a counter-clockwise direction, theend of the pawl receding from notch I29. Near the end of the two-minuteobservation period pawl screw I36 will be approaching a position onehundred eighty degrees from that shown in Fig. 11 and will engage asloping surface I3'I on a turned-down portion of latch I 33 andgradually force the latch outward.

The adjustment is such that precisely at the end of the two-minuteperiod the outer corner of 'notch I38 will be released by the latch, andshutter operating spring, I21 will cause the rotation of shaft 68 tobring about the closing of the shutter 43, as previously described.During this movement head I28 will rotate, carrying winding notch I 29around toward winding pawl I32 which, as pointed out, has already movedto a position about degress from that shown in Fig. 11. Therefore, thnext time winding knob 69 is rotated to wind the clockwork mechanism,pawl I 32 will engage winding notch I29 and return head I28 to theposition shown in Fig. 11 where it is held by latch I33.

When an observation period proceeds for the full two-minute period,resulting in the closing of shutter 43, it is important that theclockwork mechanism and the outward movement of ball transmission 20,which is continuously increasing the gear ratio between disk I 8 anddrum I9, be stopped as closely as possible to the same instant that theshutter closes. With this in view, an automatic clockwork stoppingmechanism is pro- ,vided, actuated by latch I 33.

This comprises a spring brake finger I38 (Fig. 5) adapted tofrictionally engage the surface of balance wheel 11 of the escapementmechanism 39 (Fig. 5). Finger I38 is mounted at the ,up er end of a stoplever I 39. Lever I39 is mounted for a combined lengthwise and rockingmovement alongside of index release lever III (Figs. 5 and 17). Thelower end of lever I39 is pivoted at I40 to latch I33.

In operation, when pawl screw I36, acting on sloping surface I37,finally forces the corner of latch I33 free from the corner of notch I39, the straight cam surface I3! at the right of notch I30 is quicklyrotated by the shutter-actuating spring I21 and strikes the lower edgeof latch I 33 (which has moved slightly away from it) a blow. This kickslatch I33 outwardly and moves lever I39 to bring brake finger I38instantly against the balance wheel 11. Head I28 is covered with a capwasher I4! which operatively separates the sickle-shaped index releasecam I I3 from shuttersetting pawl I32 and shutter-release latch I33.

In using the calculating instrument of the prescut invention the turningof the one winding knob 69 conditions the mechanism for operation.Furthermore, it is not necessary to know whether the value of thevariable is greater or less at the end of the averaging period than atthe beginning. In the case of a sextant therefore, the user does nothave to take into account whether the celestial body upon which thesight is being taken is ascending or declining. At the end of the sighthe simply turns control knob 3, moving index 44 in the directionindicated by the arrows on index 41, until index 44 is returned to itszero position. He then reads the counter Iii which shows the averagealtitude of the celestial body. He adds the time indicated by the timedial 4!) to the chronometer time at the commencement of the observation,to give him the time at which the celestial body reached the averagealtitude indicated by counter ID.

If it is preferred to take a series of separate sights on the celestialbody instead of using the continuous sight method, it will be understoodthat the improved averaging mechanism can be used to obtain the averagevalue of the series of altitudes measured. It is necessary to readcounter in but once, namely, after the final sight is taken and theindex .44 adjusted to zero as just described.

It will be understood that the improved mechanism of the invention has avariety of appli cations and in fact can be utilized advantageouslywherever the value to be averaged may be represented as successivemovements of an indicating member, particularly successive angularmovements of a, shaft such as shaft H. For example, the angulardisplacement of :shaft ll may be adjusted according to the powerconsumption of some particular apparatus or power system, or the poweroutput of anelectrical generating plant, or according to variations intemperature, fluid pressure, mechanical force, and the like. In adaptingthe mechanism for such use it might be desirable to increase the timerequired for the clockwork mechanism to move the ball transmission 2!]from the center to the edge of disk 13, and this might involve also anincrease of the diameter of the disk,

It will also be understood that other changes in the construction andarrangement of various parts of the mechanism may be made withoutdeparting from the spirit or scope of the invention, and consequently itis to be understood that the scope of the invention extends ,to suchconstructions as come within the meaning of the appended claims.

. We claim:

1. In an averaging device, the combination of an indicating memberarranged to move according to the value of a variable quantity, .amovable averaging member, continuously variable ratio gearinginterconnecting said members, means ior increasing said ratio at aconstant time rate during an averaging period, the movementof saidindicating member causing a displacement of the averaging member from aninitial to a final pus-i tion. the gearing interconnecting saidaveraging member and said indicating member being such that saidaveraging member may be returned to its initial position by movement ofsaid indicating member with said gearing remaining set vat the ratioestablished when said averaging member wa in said final position.

2. In an averaging device, the combination of an in icating member whoseposition s adjuste in proportion to the value of a variable quantity,

a movable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means for increasing said ratioat a, constant time rate during an averaging period, the movement ofsaid indicating member during said period causing, through thetransmission mechanism, a displacement of the averaging member and meansfor indicating the displacement of said averaging member from an initialto a final position, said transmission mechanism interconnecting saidmembers being such that said averaging member may be returned to itsinitial position by movement of said indicating member with thetransmission mech anism remaining set at the ratio established at theend of said averaging period.

3. In an averaging device, the combination of an indicating memberarranged to move according to the value of a variable quantity, amovable averaging member, a continuously variable ratio friction gearinginterconnecting said members adapted to change its ratio whilemaintaining a driving connection between said members regardless ofwhether said indicating member is stationary or moving, means forincreasing said ratio at a constant time rate, the movement of saidindicating member causing, through said gearing, a displacement of theaveraging member and means for indicating the displacement of saidaveraging member from an initial to a final position, the gearinginterconnecting said averaging member and said indicating member beingsuch that said averaging member may be returned to its initial positionby movement of said indicating member with the friction gearingremaining at the ratio established when said averaging member was atsaid final position.

4. In an averaging device, the combination of an indicating member whoseposition is adjusted in proportion to the valueof a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means for increasing said ratioat a constant time rate during an averaging period, the movement of saidindicating member during said period causing, through the transmissionmechanism, a displacement of the averaging member from an initialposition to a final position, and means for indicating the position ofthe averaging member said transmission mechanism being such that thefinal position of the averaging member may be modified by movement ofthe indicating member while the transmission mechanism remains set atthe ratio established at the end of said averaging period until theaveraging member has been returned to its initial position.

5. In an averaging device, a disk adapted to have angular adjustmentabout its axis in proportion to the value of a variable quantity, meansfor indicating the angular displacement thereof, a rotatable cylindricaldrum having its axis parallel to the face of the disk and intersectingthe projectionof the disk axis, a continuously variable ratio frictiongearin interconnecting said disk and drum adapted to change its ratiowhile maintaining a driving connection between said disc and said drumregardless of whether said disk is stationary or moving, means forincreasing said ratio at a constant time rate during an averagingperiod, the movement of said disk during said period causing, throughsaid friction gearing, an angular displacement of the drum from an iniial to a-final position, and means for indicating the angular positionof the drum, said 17. gearing being such that the position assumed bythe disc at the end of an averaging period may be modified by movementthereof while the friction gearing remains set at the ratio establishedat the end of said averaging period until the drum has been returned toits initial position.

6. In an averaging device, a disk adapted to have angular adjustmentabout its axis in proportion to the value of a variable quantity, meansfor indicating the angular displacement thereof, a rotatable cylindricaldrum having its axis parallel to the face of the disk and intersectingthe projection of the disk axis, a continuously variable ratiotransmission mechanism interconnecting said disk and drum comprising twoballs held in rotatable contact with each other and with said members,means for increasing said ratio at a constant time rate during anaveragin period, the movement of said disk during said period causing,through said transmission mechanism, an angular displacement of the drumfrom an initial to a final position, and means forindicating the angularposition of the drum said transmission mechanism bein such that theposition assumed by the disc at the end of an averaging period may bemodified by movement thereof while the transmission mechanism remainsset at the ratio established at the end of said averaging period untilthe drum has been returned to its initial position.

7. In an averaging device, a disk adapted to have angular adjustmentabout its axis in pro portion to the value of a variable quantity, meansfor indicating the angular displacement thereof, a rotatable cylindricaldrum having its axis parallel to the face of the disk and intersectingthe projection of the disk axis, mechanism for transmitting motionbetween two points on the respective surfaces of the disk and drum, saidpoints lying in a straight line intersecting the drum axis at rightangles, a clockwork mechanism for shifting said transmission mechanismat a constant velocity radially outward from the center of the diskthereby causing, through said transmission mechanism, an angulardisplacement of said drum from an initial to a final position and meansfor indicating the angular position of said drum to enable the finalposition of said drum to be modified by movement of said disc while thetransmission mechanism remains set at the ratio established at the endof an averaging period until said drum has been returned to its initialposition.

8. In an averaging device, the combination of an indicating memberarranged to move in proportion to the value of a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means for increasing said ratioat a constant time rate during an averaging period, the movement of saidindicating member durin said period causing a displacement of theaveraging member from an initial position to a final position, means forindicating the position of the averaging member said transmissionmechanism being such that the final position of the averaging member maybe modified by movement of the indicating member while the transmissionmechanism remains set at the ratio established at the end of anaveraging period until the averaging member has been returned to itsinitial position, and means for indicating the direction of said returnmovement of the averaging member to its initial position.

9- In an averaging device, the combination of an indicating memberarranged to move in proportion to the value of a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means for increasing said ratioat a constant time rate during an averaging period, the movement of saidindicating member during said period causing displacement of theaveraging member, means for indicating the extent of said displacementcomprising an index dial adapted to be turned proportionally to thedisplacement of said averaging member said transmission mechanisminterconnecting said averaging member and said indicating member beingsuch that said averaging member may be moved from the position assumedat the end of the averaging period until said index dial registers theposition indicated at the beginning of the averaging period, while saidtransmission mechanism remains set at the ratio established at the endof the averaging period.

10. In an averaging device, the combination of an indicating memberarranged to move in proportion to the value of a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means for increasing said ratioat a constant time rate during an averaging period, the movement of saidindicating member during said period causing displacement of theaveraging member from an initial position to a final position, and meansfor indicating the direction and extent of said displacement comprisinga pair of index dials, operative connections for turning said dials froma zero position proportionally to the displacement of said averagingmember, one of said dials turning at a lower rate than the saidoperative connections including a releasable clutch mechanism for eachof said index said clutch mechanisms are released.

11. In an averaging device, the combination of an indicating memberarranged to move in proportion to the value of a variable quantity, arotatable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means for increasing said ratioat a constant time rate during an averaging period, the movement of saidindicating member during said period causing displacement of theaveraging member from an initial position to a final position, means forindicating the direction said dials from a zero position proportionallyto the displacement of said averaging member, one of said dials turningat a lower rate than the other, said connections including a releasableclockwork mechanism.

12. In an averaging device, the combination of an indicating memberarranged to move in proportion to the value of a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, means vfor increasingsaid ratioat a constant time rate during an averaging period, the movement of saidindicating member during said period causing displacement of theaveraging member, means for indicating the extent of said displacementcomprising an index dial, an operative connection including a releasableclutch mechanism for turning said dial from a zero positionproportionally to the displacement of said averaging member, means toreset said dial at zero when the clutch mechanism is released, .awinding device for winding said clockwork mechanism, and means actuatedthereby for releasing saidclutch mechanism to cause said index dial tobe reset simultaneously with the winding of the clockwork mechanism.

13. In an averaging device, the combination of an indicating memberarranged to move in proportion to the value of avariable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, a clockwork mechanism forincreasing said ratio at a constant time rate during an averaging periodcommencing at zero ratio at the beginning of the period, the movement ofsaid indicating member during saidperiod causing a displacement of theaveraging member, means .ior indicating the position of the averagingmember, and a singlemeansior winding saidlclockwork mechanism andsimultaneously settingsaid transmission mechanism at zero .ratio.

is. In an averaging device, thercombination of an indicating memberarranged to movein proportion to the value of a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, a clockwork mechanism forincreasing said ratio .at a constant time rate during a predeterminedaveraging period commencing .at zero ratio at the beginning of theperiod, the movement of said indicating member during said periodcausing a displacement of the averaging member, means for indicating theposition of the averaging member, automatic means for stopping saidclockwork mechanism at the end of said averaging period, and means forwinding said clockwork mechanism and simultaneously releasing saidstopping means.

,15 In an averaging device, the combination of anindicatin memberarranged to move in proportion to the value of a variable quantity, amov able averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, a clockwork mechanism forincreasing said ratio at a constant time rate during .a predeterminedaveraging period commencing at zero ratio at the beginning of theperiod, the movement of said indicating member during said periodcausing a displacement of the averaging member, means for indicating theposition of the averaging member, automatic means for stopping saidclockwork mechanism at the end of the averaging period, and means forwinding saidclockwork mechanism and simultaneously setting saidtransmission mechanism at zero ratio and releasing said stoppingmechanism.

16. The combination with a sextant or the like, having a light pathincluding an eye-piece and an angularly adjustable mirror, of anaveraging mechanism comprising a pivoted indicating member operativelyconnected with said mirror to cause the angular position thereof to beadjusted in proportion to the adjustment of the mirror, a movableaveraging member, a continuously variable ratio transmission mechanisminterconnect ing said members, .a clockwork mechanism for in creasingsaid ratio at a constant time rate during a predetermined averagingperiod commencing at zero ratio at the beginning of the period, theangular movement of said indicatingmember during said period causing adisplacement of the averaging member, means for indicating the positionof the averaging member, a spring-operated shutter biased into saidlight path between the mirror and eye-piece, latching means for holdingsaid shutter out of the light path during the averaging period,automatic means for tripping said latching means at the end of saidaveraging period, and means for winding said clockwork mechanism andsimultaneously setting said shutter.

17. In an averaging device, the combination of an indicating memberarranged to move in pro-v portion to the value of a variable quantity, amovable averaging member, a continuously variable ratio transmissionmechanism interconnecting said members, a clockwork mechanism for.increasing said ratio at a constant time rate during an averagingperiod, the movement of said indicating member during said periodcausing a displacement of the averaging member, means tor indicating theposition of the averaging member, and means for winding said clockworkmechanism comprisin a winding knob, a shait therefor, a second shaft inalignment therewith and operatively connected to wind :said clockworkmechanism in less than a full turn of said shaft, unidirectionalconnecting means between said shafts to cause the turning of said secondshaft by the winding knob shaft, and a spring biasing the winding knobshaft in a direction to disengage said connecting means so that contactof the users hand with the Winding knob during an averaging period willnot retard the clockwork mechanism.

18. In an averaging device, a disk adapted to have angular movementabout its axis in proportion to the value of a variable quantity, means.for indicating angular displacement thereof, a movable averaging member,a carriage. supporting two balls in rotatable contact with each otherand with said disc and said averaging member respectively, means formounting said carriage to move parallel to the face of the disk carryingsaid balls from the center of the disk radially outward, spring meansfor biasing said carriage in the outward direction, a balance wheel andescapement mechanism actuated by the carriage to control its movement ata constant rate, movement of the disk being communicated to theaveraging member through said balls, means for indicating the resultingdisplacement of said averaging member and means to stop the movement ofsaid carriage and hold it in the position :assumed when stopped so thatthe averaging member may be returned to its initial position withoutchanging the position of said carriage.

19. In an averaging device, a disk to have angular movement about itsaxis in proportion to the value of a variable quantity, means forindicating the angular dispiacement, thereof, a rotatable cylindricaldrum having its axis parallel to the face of the disk and mtersectingthe projection of the disk axis, a carriage supporting two ballsinrotatable contact with each other and with the disk and drumrespectively, means for mounting said carriage to move parallel to theface of the disk carrying :said balls from the center of the diskradially outward, a spring means biasing said carriage in the outwarddirection, a balance wheel and escapement mechanism actuated by saidcarriage to control its movement at a constant rate, movement of thedisk being communicated to the drum through said balls, means forindicating the resulting angular displacement of the drum and means tostop the movement of said carriage and hold it in the position assumedwhen stopped so that the averaging member may be returned to its initialposition without changing the position of said carriage.

20. The combination with a sextant or the like having an altitudeindicator of an averaging mechanism comprising a pivoted memberoperatively connected to said altitude indicator to cause the angularposition of said ivoted memher to be registered by said altitudeindicator, a movable averaging member, a continuously variable ratiotransmission interconnecting said members, a clockwork mechanism forincreasing said ratio at a constant time rate during an averagingperiod, the angular movement of said pivoted member causing adisplacement of said averaging member, means for indicating the finaldisplacement of said averaging member, said pivoted memberbeing soconnectedto said averaging member that said averaging member may bereturned to its initial position by movement of said pivoted memberwhile said transmission remains at the ratio established at the end ofthe averaging period thereby enabling the average altitude to be read onsaid altitude indicaton 21. The combination with a sextant or the likehaving an altitude indicator of an averaging mechanism comprising amovable disk operatively connected to said altitude indicator to causethe position of said disk to be indicated by said indicator, arevolvable drum, a continuously variable ratio transmissioninterconnecting said disk and drum, a clockwork mechanism for increasingsaid ratio at a constant time rate during an averaging period, means tostart and stop said clockwork mechanism, the movement of said diskcausing a displacement of said drum, means for indicating thedisplacement of said drum at the time said clockwork is stopped, saiddisk being so connected to said drum that said drum may be returned toits initial position by movement of said disk while said transmissionremains at the ratio established at the end of the averaging periodthereby enabling the average altitude to be read on said altitudeindicator.

22. In a sextant or the like having an altitude indicator, an averagingmechanism comprising an indicating member operatively connected to saidaltitude indicator and adapted to move therewith, a movable averagingmember, a continuously variable ratio transmission mechanisminterconnecting said members including two balls held in rotatablecontact with each other and said members respectively, means forincreasing the ratio of said transmission at a constant time rate, themovement of said indicating member causing through the transmissionmechanism a displacement of the averaging member and means forindicating the resulting displacement of said averaging member from aninitial to a final position, said transmission mechanism being soarranged that said averaging member may be returned to its initialposition by movement of said indicating member with the transmissionremaining set at the ratio established at the final position of saidindicating member thereby enabling the average altitutde to be indicateddirectly by the altitude indicator.

23. In a sextant or the like having an altitude indicator, thecombination of an averaging mechanism comprising a disc mounted forangular adjustment about a central axis operatively connected to saidaltitude indicator. a cylindrical drum having its axis parallel to theface of the disc and intersecting the projection of the disc axis,mechanism for transmitting motion between two points on the respectivesurfaces of the disc and drum, said points lying in a straight lineintersecting the drum axis at right angles, means for shifting thetransmission mechanism radial- 1y outward from the center of the disc ata constant time rate, the disc being angularly adjusted simultaneouslyby movement of the altitude indicator and causing through thetransmission mechanism angular displacement of the drum, means forindicating the initial position and the final position of said drum,said transmission mechanism being such that the indicating means may beturned back to its initial position by movement of the altitudeindicator with the transmission mechanism remaining set at the radialdistance assumed at the final displaced position of said drum so thatthe average altitude ma be read directly on the altitude indicator.

RICHARD FRANCIS DEIMEL. WILLIAM ALEXANDER BLACK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 765,531 Weston July 19, 1904864,379 Junghans Aug. 27, 1907 1,409,547 Hosch, Deccl. Mar. 14, 19221,439,097 Graham Dec. 19, 1922 2,140,579 Gray Dec. 20, 1938 2,248,072Fry July 8, 1941 2,252,341 Everitt Aug. 12, 1941 2,285,856 Everitt June9, 1942 2,337,045 Holt Dec. 21, 1943

